Fossil Molds and Casts: Making Fossils (page 2)
Fossils are the remains or impressions of once-living plants and animals. The best impressions are made from the hard parts of an organism, but the soft areas, such as skin and scales, can also be preserved under the right conditions. An impression of a fossil is called a mold, the space or hole left by an organism's body. Over time that space can be filled with minerals and sediment that harden into a cast. In this activity you will make molds of both soft and hard objects.
Coin or some other hard object
- Divide the modeling clay into two piles.
- Mold both clay piles into pancake shapes.
- Put the coin on the desk and press one clay pancake over the coin.
- Carefully peel the clay away from the coin, trying not to deform the mold you made.
- Repeat this process with the leaf.
- Compare your two molds.
- Which made the better impression, the coin or the leaf? Why?
- Explain how this activity is similar to what occurs when a fossil is being made.
- If you filled in your mold with plaster of paris, what would the hardened material inside the mold be called?
- The coin—it is easier to press the clay around a firm object.
- When an organism dies, it makes a mold in soft sediment. The mold gets filled with material that forms a cast.
Make a cast from the molds you made. Mix 10 teaspoons of plaster of paris with 5 teaspoons of water. Pour the liquid material into the molds and allow them to harden. Separate the clay from the plaster of paris cast. How does the cast compare to the original items?
- Kindergarten Sight Words List
- Coats and Car Seats: A Lethal Combination?
- Signs Your Child Might Have Asperger's Syndrome
- Child Development Theories
- The Homework Debate
- Social Cognitive Theory
- GED Math Practice Test 1
- 10 Fun Activities for Children with Autism
- Why is Play Important? Social and Emotional Development, Physical Development, Creative Development
- First Grade Sight Words List